STUDIES ON MODE OF ACTION OF SOME CEPHALOSPORIN DERIVATIVES

7‐(s‐benzylthioacetamido)‐cephem‐3‐ylmethyl‐N‐dimethyldithiocarbamate‐4‐carboxylic acid (cephalosporin 7/30) prevented benzylpenicillin from inducing spheroplasts in Escherichia coli, and inhibited growth of preformed spheroplasts. These effects were also noted with dimethyldithiocarbamate (DMDT), the side‐chain at position 3 in 7/30. Cephalosporin 7/30 inhibited growth of protoplasts of Bacillus megaterium and Streptococcus faecalis. At high concentrations, 7‐[(2‐thienyl)acetamido]‐cephem‐3‐ylmethyl‐N‐dimethyldithiocarbamate‐ 4‐carboxylic acid (cephalosporin 87/30), with the same side‐chain at 7 as cephaloridine but with DMDT at position 3, prevented spheroplast formation in E. coli, and inhibited the growth of preformed spheroplasts. However, at lower concentrations, 87/30 induced spherical forms in E. coli. The other cephalosporins, tested induced spheroplasts in E. coli and had no effect on protoplasts. Copyright © 1969, Wiley Blackwell. All rights reserved